OK, now I'm a little confused. Understanding all the properties of moly coating, does it NEED to be removed from barrels because of the potential rust problems or leave the coating in the barrel to protect it from continued wear due to friction? Or, am I splitting hairs here?
kevinh
That is exactly the big debate about moly (or "the other disulfide"... Tungsten Disulfide) coatings. You can spend days reading info on the subject...be in on the net or in books and gun rags...and still come away confused on the subject.
Yes, a moly coating will reduce friction and wear on the rifling.
Yes, it can be a stinker to clean from a bore if you get an excessive buildup (many times caused by home-coated bullets with too much lube on them as I understand).
Yes, the heat & pressure inside the barrel from the shooting process will convert some of the disulfide coating into a sulfite compund which can react with moisture in the air and cause corrosion. Just keep the bore oiled between sessions and this isn't a problem.
I personally haven't done much of anything with moly bullets so I would have to say that 10 Spot's experience holds more validity than any info I can give.
I've shot a few moly bullets, but haven't done any serious load development with them.
I bought a pair of .22-250 prairie dog rifles from a local fellow that had a steady diet of moly bullets. Both needed a SERIOUS cleaning when I bought them. the guy had 500-1000 rounds through each and they just wouldn't group anymore. He though the throats were gone, but after much scrubbing (copper and moly fouling) they both came back to shooting sub-MOA groups.
The stainless barreled Rem700 is just fine.
The blued Savage does have very fine pitting in the bore, but doesn't affect groups beyond my satisfaction. It's just a stinker to get the copper fouling out of that barrel now. I can't say for sure that pitting was caused by sulfite corrosion....
I think if I did try another non-friction coating it would be HBN, because when it breaks down it won't form a corrosive sulfite.